A standard contact assembly has a dielectric mounting block having inner and outer faces and at least one conductive contact unitarily formed of elastically deformable metal. This contact has a center web set in the block, an inner leg extending from the web past the inner face and elastically deflectable toward the inner face and toward the center web, and an outer leg extending from web and elastically deflectable from an outer position spaced well outward of the outer face and spaced from the web to an inner position closely juxtaposed with or even touching the web.
Such a contact assembly can be mounted, for example, in a wall of a cell phone, between the openable battery compartment and the interior compartment holding the phone's circuitry. Each inner leg bears on and makes permanent electrical contact with a trace of the printed-circuit board carrying this circuitry. Each outer leg can bear on a terminal of a removable battery, typically of the replaceable and rechargeable type. British patent 833,038 of R. Firman, German patent 3,338,080 of G. Muscaglione, and German patent 198 34 375 of K. Bauer describe typical such contact assemblies. Three contacts are provided normally on one mounting block to allow three electrical connections to be made to the battery.
In today's very small electronic equipment, in particular cell phones, it is important that every element be made as compact as possible. The above-described contact assemblies however cannot be reduced beyond a certain thickness, is as otherwise the outer leg at least will not bear with sufficient force against the battery terminals to form a good long-term electrical connection. The stroke of the outer leg must be maximized to ensure that it is deformed considerably in its inner contacting position, and this relatively long stroke takes up valuable space inside the device it is mounted in.